docs: def create_from_tuple(cls, volume):
          """
          Create instance from tuple.
          :param volume: tuple in one one of the following forms: target | source,target | source,target,mode
          :return: instance of Volume
          """
          if isinstance(volume, six.string_types):
              return Volume(target=volume)
          elif len(volume) == 2:
              return Volume(source=volume[0],
                            target=volume[1])
          elif len(volume) == 3:
              return Volume(source=volume[0],
                            target=volume[1],
                            mode=volume[2])
          else:
              logger.debug("Cannot create volume instance from {}."
                           "It has to be tuple of form target x source,target x source,target,mode.".format(volume))
              raise ConuException("Cannot create volume instance.")